1950 Plymouth Three Window Coupe - Ramrodder: Part II - Tech

Here the left side has been straightened, indentation has been trimmed, reshaped with a hammer and dolly and tack welded in place.

With all cuts welded solid it was time to fill all the holes (and there were a bunch of them) and the newly-created gaps on each side.

Prior to filling any holes a hammer and dolly was used to flatten the edges of them all.

To weld small holes closed with a wire-feed welder without filler plugs we used a copper backup paddle from Eastwood.

Where access is available the paddle is held against the backside of the panel--the welding wire won't stick to it and the hole can be welded solid.

For larger openings, such as the hole for the original heater, paper patterns were made and patches were cut from sheetmetal.

To prevent warpage the larger patches were secured with a series of tack welds until the panel was welded solid.

After the patches were welded in place a rigid grinding wheel was used to grind down the beads. A rigid disc will hit only the high spots of the weld, not the surrounding metal, which doesn't need to be removed.

Once the weld bead is ground down a flexible 80-grit disc can be used to blend the surrounding area.

With the filler plates added to the edges of the firewall the before and after shape is obvious.

The end result of all the cutting, grinding, hammering and filling was an additional 2 inches in the engine compartment where we needed it: behind those big Hemi heads.

Tex was right, by leaving all the factory indentations, ribs and other lumps and bumps and adding a coat of primer the firewall modifications are not readily apparent.